Can vacancies be the main reason of FeAl alloys hardening?

The literature provides quite a lot of facts against the ‘vacancy hardening’ as the main cause of FeAl alloys hardening. The compositional dependency of the vacancy concentrations has been investigated and related to room temperature yield stress of the FeAl alloys.Thermal point defects concentration was measured in a FeAl based alloy and applied to calculate the high temperature strengthening. The studies have shown that vacancies are not the main reason of FeAl alloys hardening.